This invention relates to an artificial joint which is intended in particular for replacement of an ankle joint and has a first main articular surface which forms a joint socket and is intended in particular for replacement of the tibia, composed of concave curvatures parallel to a main function plane of the joint which corresponds to the sagittal plane and with a second main articular surface which is mechanically linked to the first main articular surface as part of a condyle which replaces the talus in particular with curvatures that are concave in the main function plane and are coordinated with the first main articular surface, in which the radii of the convex curvatures of the second main articular surface are smaller than those of the corresponding curvatures of the first main articular surface.
Artificial joints of this type are used in practice in a variety of ways, e.g., to replace the ankle joint and are therefore known from prior public use. The condyle, as the basic form of such joints, is designed to be spherical or cylindrical, for example, and therefore permits one or more degrees of freedom. The corresponding articular surfaces have a difference which corresponds to the desired tolerance and must, in particular, comply with the requirements for a high load-bearing capacity and a low mechanical wear at the same time.
In medical practice, however, it has been found that the properties of natural joints can be simulated only very inadequately using the known artificial joint. In particular, it is not possible using the known artificial joint to achieve the properties of natural joints which are suitable for transmitting high forces under load while at the same time having a high measure of mobility under reduced loads. As a result, the desired mobility must often be sacrificed in order to achieve increased long-term load-bearing capacity.